Answer:
y = -
x + 1
Explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Calculate m using the slope formula
m =

with (x₁, y₁ ) = (0, 1) and (x₂, y₂ ) = (4, - 1) ← 2 points on the line
m =
=
= -

The line crosses the y- axis at (0, 1 ) ⇒ c = 1
y = -
x + 1 ← equation of line